Carburetor



Oct. 18, 1932.

A. P. PLAUT 1,882,877

CARBURETOR Filed Oct. 21, 1929 2 Sheets-Sheet l Mama 7? 2/4 an ATTORNEY Oct. 1 1932.

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CARBURETOR 2 Sheet 2 Filed Oct. 21. 1929 INVE R finzazwei t ATTO s Patented Oct. 18, 1932 UNITED STATES PATEN OFFICE ANTOIN'E P. PLAUT, OF FLINT, MICHIGAN, ASSIGNOR TO MARVEL OARBURETOR COM? PANY, OF FLINT, MICHIGAN, A CORPORATION OF MICHIGAN CARBURETOR Application filed. October 21, mag. Serial no. 401,240.

The invention relates to carburetors and more particularly to carburetors of the socalled plain tube type wherein the proper proportions of fuel'and air are automatical- 1y maintained by providing the proper calibration of fuel and air controlling devices. The principal object of the invention is to provide a carburetor having a fuel passage leading into the main air passage below the 19 throttle valve and to provide a transfer passage leading from the main fuel passage and extending to a point in the main air passage above the throttle valve. It is a further object of the invention to so construct the transfer passageway and the various air and fuel passages so that the right amount of fuel is delivered to the main air passage under idling conditions, low speed conditions, or high speed conditions as the case may be.

TVhile my invention is capable of embodiment in various different forms, it may best be explained by reference to the accompanying drawings of a preferred construction.

Figure 1 represents a plan view of a carburetor with certain portions broken away to reveal a fuel transfer passage 60; Y

Figure 2 is a side elevation of the carburetor, parts being broken away to show the fuel and air passages, the section being taken substantially on the line 22 of Figure 1;

Figure 3 is a fragmentary view of a portion of the apparatus shown in Figure 2 wherein the section is shown along the line 33 of Figure 1;

Figure 4 is a sectional elevation of the carburetor on the line 44 of Figure 1;

Figure 5 is a horizontal section on the line 55 of Figure 4;

Figure 6 is an enlarged detail view of the vertical suction tube, the section being taken on the line 66 of Figure 2.

Referring now to the carburetor construction illustrated in the drawings, 1 represents the main air entrance, 2 the mixture outlet, 3 the constant level fuel reservoir. The main air passage extends horizontally from the entrance 1, preferably through a Venturi choke tube and leads into a valve housing 31 wherein the passage is directed downwardly through the vertical tubular portion 32 to the Cir mixture outlet 2. Within the valve housing 31 is arranged a throttle valve", which in the present instance is, of the barrel valve type. This throttle valve 33 may be of any suitable construction but, as shown, consists of a hollow shell rotatable within the cylindrical bearing 34 in the housing and having a port opening 35 adapted to register with the passage through the Venturi choke tube 30. The valve is opened at the lower side thereof as indicated at 36 forming communication at all times with the vertical mixture passageway 32. For controlling the valve 33 there is provided a stem 37 extending axially through an upper bearing 38 and provided at its outer end with a suitable actuating lever 39. Movement of the lever 39 causes the port opening 35 to move out of registration with the passage through choke tube 30, thereby restricting the passageway to the extent desired inorder to control the carburetor. The venturi 30 may be of any suitable construction but preferably is made in accordance with my previous Patent No. 1,625,867.

From the fuel reservoir 3 there is a downwardly extending arm 10 which terminates in a laterally extending portion 11 forming a support for the jet housing 42. WVithin the arm 10 there, is the diagonally downward bore or fuel passage 40 which intersects a horizontal bore a l which in turn leads to an opening 13 in the jet housing support. The jet housin 42 is apertured at 43 forming an accelerating chamber 44. 45 is a threaded inwardly extending abutment adapted to receive the nozzle tube 46. The upper end of the nozzle tube is received within a vertical bore 4:? and this end of the nozzle is provided with a calibrated opening 48 designed to admitall of the fuel necessary to the operation of the carburetor.

' From the vertical bore 47 there extends a substantially horizontal transverse emulsion conveying tube 49, the outer end 19' ofwhich is curved upwardly and extends through the choke tube 30 into the main air passage 29. This tube is provided with an enlargement 50 into which extends the lower end of a vertical suction tube-51. A passage-16 extends between the bottom of the enlarged chamber 50 and the accelerating chamber From the top of the jet housing 42 there extends downwardly an air flue passage 8 which comniunicates with the vertical bore 47 by means of two or more transverse air flues 9. A vertical passage 17 extends between the lowermost air fiue 9 and the accelerating chamber 44.-

For admitting air to the main air flue 8 and regulating the same a tubular structure 53 is provided above the jet housing This tubular structure has avent opening 55 communicating with the atmosphere and a second passageway 58 leading from a point in the air inlet 1 in advance of the Venturi choke tube 30. Thus air is supplied to the air flue passage 8 either from the atmosphere or from the entrance of the choke tube or from both.

The vertical suction tube 51 leads upwardly to a transfer passage which in turn extends to a point adjacent to the casing for the throttle valve 33. 61 is a passa eway extending through the casing 31 into the main air passage at a point beyond the throttling point of the va ve 33. The passages (it) and 61 communicate with each other and are controlled by a needle valve 62 which is adjust able by means of the adjusting screw As heretofore pointed out, the vertical suction tube 51 extends within the enlargement 50. It is desirable that the opening at the bottom of the suction tube 51 be arranged in predetermined relation to the bottom of the enlargement 50 and for convenience in determining the position of the opening, the tube 51 is preferably beveled, thus forming the opening 64 in the beveled side of the tube as indicated in Figure 6.

l/Vith the carburetor as above described, the fuel is normally maintained at the level AA. The fuel from the reservoir 3 passes downwardly through passages 40 and 41 and upwardly through the fuel nozzle 46, cali brated orifice 48 and fills the passages 47, 8, 9, 49 and 50 to the level AA. The lower end of the tube 51 is thus submerged. The accelerating chamber is normally filled by overflow through the vertical passages 16 and 17.

WVhen the carburetor is functioning, the fuel is delivered to the mixing chamber through the calibrated orifice 48 and the amount of fuel flowing through this orifice is determined by the depression in the passage 47 immediately above the fuel nozzle. The depression at this point is a function of the ratio between the area of the air passage 8 and the tube 49.

The fuel which issues from the calibrated orifice 48 is caught by a current of air through the transverse air flues 9 and is carried toward or into the main tube 49. From this point there are two routes by which the fuel may be introduced into the mixing chamber of the carburetor, either through the outlet 19 of the tube 49 to the portion of the mixture chamber anterior to the throtting point, or through the suction tube 51 and transverse passage 60 to the portion of the mixing chamber posterior to the throttling point. Under wide open throttle conditions the fuel passes mainly through the tube 49 and outlet 19. Vvith a throttled motor, however, the velocity in the air entrance 1 is very low even with a speed corresponding to twenty miles per hour of a motor vehicle and it is desirable up to that point to transfer all of the fuel to the mixture passageway by quicker and more positive means than the tube 49. F or this purpose I employ enlarged passageway 50, the suction tube 51 and the transfer passage 60. l/Vhen the fuel reaches this enlarged passageway50 it loses its velocity because of the enlargement and the fuel practically stops moving for a short time. The depression in the fuel transfer passageway 60 is at the same time a multiple of what it is in the enlargement 50 and therefore any fuel in the enlarged passageway is picked up by the suction tube 51 and transferred quickly beyond the throttle opening. In a properly calibrated carburetor the depression in the passageway 50 will be equal to that in the transverse passageway 60 at about forty-five to fifty miles per hour and therefore theoretically all of the fuel should go through the transfer passageway 60 up to that speed but a stage is reached when on account of its velocity the fuel can not be intercepted in the enlargement 50 for a long enough period to be picked up by the suction tube 51 in its entirety. Therefore the fuel does-not all pass through the suction tube 51 after a speed of twentyiive miles per hour.

In the operation of the carburetor, assumingthat the engine has started and the throttle is now in position for idling, the fuel level will be slightly below the. line AA. The suction tube 51 extending into the enlargement 50 will intercept fuel providing the fuel level is not too far below the top of the opening 64 in the bevel side of the tube. There being a high suction in the suction tube, the fuel is quickly transferred to the mixing chamber and the fuellevel in the enlargement 50 is constantly kept down to a point below the normal level AA. Under conditions of acceleration, that is when the throttle is suddenly opened, the suction will of course be increased on the tube 49, thus increasing the flow through the calibrated orifice. This increased suction effective in the enlargement 50 will cause fuel to riseupwardly within the air inlet, a mixture outlet, a throttle at the mixture outlet end, a mixing chamber between said air inlet and mixture outlet, an emulsion passage leading into said mixing chamber, nozzle means for supplying substantially all of the fuel utilized by said carburetor to said emulsion passage, means for admitting air to said emulsion passage, said emulsion passage being provided with an enlargement between the discharge end thereof on the one hand and the nozzle means and the air admitting means on the other hand, said enlargement being at a higher level than said nozzle means, said emulsion passage having a horizontal portion extending from said enlargement toward said mixing chamber and a transfer passageway having one end thereof connected to the mixture outlet above the throttle and the other end extending into said enlargement.

2. In a carburetor, the combination of an air inlet, a mixture outlet, a throttle at the mixture outlet end, a mixing chamber between said air inlet and mixture outlet, an emulsion passage leading into said mixing chamber, nozzle means for supplying substantially all of the fuel utilized by said carburetor to said emulsion passage, means for admitting air to said emulsion passage, said emulsion passage being provided with an enlargement between the discharge end thereof on the one hand and the nozzle means and the air admitting means 011 the other hand and a transfer passageway having one end thereof connected to the mixture outlet above the throttle and the other end connecting with said enlargement, an accelerating chamber, a passageway leading from said accelerating chamber to said enlargement and a second air passage leading into said accelerating chamher.

3. In a carburetor, the combination of an air inlet, a mixture outlet, a throttle at the mixture outlet end, a mixing chamber between said air inlet and mixture outlet, an emulsion passage leading into Said mixing chamber, nozzle means for supplying substantially all of the fuel utilized by said carburetor to said emulsion passage, means for admitting air to said emulsion passage, said emulsion passage having an upwardly extendin portion and having a laterally extending portion between said upwardly extending portion and said mixing chamber, said laterally extending portion having an enlargement between the discharge end of said emulsion passage on the one hand and the nozzle means and the air admitting means on the other hand, said enlargement being at a higher level than said nozzle means said emulsion passage having a horizontal portion between said enlargement and said upwardly extending portion and a transfer passageway having one end thereof connected to the mixture outlet above the throttle and the other end extending into said enlargement.

4:. In a carburetor, the combination of an air inlet, a mixture outiet, a throttle at the mixture outlet end, a mixing chamber between said air inlet and mixture outlet, an

emulsion passage leading into said mixing chamber, nozzle means for supplying substantially all of the fuel utilized by said carburetor to said emulsion passage, means for admitting air to said emulsion passage, said emulsion passage having an upwardly extending portion and having a laterally extending portion between said upwardly extending portion and said mixing chamber, said laterally extending portion having an enlargement provided with a depressed lower surface, said enlargement being located above the level of said nozzle means said emulsion passage having a horizontal portion between said enlargement and said upwardly extending portion and a transfer passageway having one end thereof connected to the mixture out let above the throttle and the other end extending into said enlargement adjacent said depressed lower surface.

5. In a carburetor, the combination of an air inlet, a mixture outlet, a throttle at the mixture ouuiet end, a mixing chamber between said air inlet and mixture outlet, an emulsion passage leading into said mixing chamber, nozzle means for supplying substantially all of the fuel utilized by said carburetor to said emulsion passage, means for admitting air to said emulsion passage, said emulsion passage having an upwardly extending portion and having a laterally extending portion between said upwardly eX- tending portion and said mixing chamber, said laterally extending portion having an enlargement provided with a depressed lower surface, said enlargement being located above the level of said nozzle means said emulsion passage having a horizontal portion between said enlargement and said upwardly extending portion and a transfer passageway having one end thereof connected to the mixture outlet above the throttle, the other end of said transfer passageway terminating in a tubular member extending into said enlargement with the lower end thereof substantially contacting with said depressed lower surface, said tubular member having an opening in the side thereof.

In testimony whereof I afiix my signature.

ANTOINE P. PLAUT.

CERTEFECATE OF CORREQTEON.

Patent N0. 1,882,877. Octsber '18; E932.

ANTGENE P. PLAUE.

It is hereby cerrifis that the above numbered pawns was erroneously issued to "Marvel Carburetsr Camparxy", as assigares 0f the entire interest in said inventios, whereas said parent Silesia: have besn issued tr) the invents! said "Plant" and fire iarve! @arbursi-sr Qempany", as assignss 0f sire-half interest rmly as shevm by the records of assignments in this efiies; and that the said Letters Patent shculd be rss wish ihis correction therein that the same may conform t0 the record of the case the Patent Office Sfigned and seaie-fl this 24th day sf January, A. D. 1933.

M, J. Moore, (Sea!) Fasting Commissioner of Parents. 

